The U.S. Food and Drug Administration is alerting pet owners and veterinarians to be aware of the potential for neurologic adverse events in dogs and cats when treated with drugs that are in the isoxazoline class.

Since these products have obtained their respective FDA approvals, data received by the agency as part of its routine post-marketing activities indicates that some animals receiving Bravecto, Nexgard or Simparica have experienced adverse events such as muscle tremors, ataxia, and seizures. Another product in this class, Credelio, recently received FDA approval. These products are approved for the treatment and prevention of flea infestations, and the treatment and control of tick infestations.

The FDA is working with manufacturers of isoxazoline products to include new label information to highlight neurologic events because these events were seen consistently across the isoxazoline class of products.